1. Field of the Invention
The present invention relates to asphalt compositions, to asphalt products made from such asphalt compositions, and to methods of making and using such compositions and products. In another aspect, the present invention relates to asphalt compositions which may be readily applied to surfaces using common equipment and techniques, to asphalt surfaces formed therefrom, and to methods of making and using such compositions and surfaces. In even another aspect, the present invention relates to asphalt compositions using for making thin and ultrathin paving layers, and to method for making and using such compositions and layers. In still another aspect, the present invention relates to asphalt compositions useful in making a non-tracking, hot applied tack coat for bonding two layers of hot mix asphalt together, to non-tracking, hot applied tack coats, to multiple layer surfaces in which the top coat is a non-tracking, hot applied tack coat, and to methods of making and using the foregoing. In yet another aspect, the present invention relates to asphalt compositions comprising a high Pen (i.e., flexible) asphalt, and to products made therefrom, and to methods of making and using such compositions and products. In even still another aspect, the present invention relates to asphalt compositions comprising a lower rotational viscosity asphalt (especially in combination with maintaining a higher softening point), and to products made therefrom, and to methods of making and using such compositions and products. In even yet another aspect, the present invention relates to asphalt compositions comprising a more ductile asphalt to provide products made therefrom some capability of stretching or movement under traffic loading or weather related expansion and contraction, and to products made therefrom, and to methods of making and using such compositions and products. In still even another aspect, the present invention relates to asphalt compositions comprising an asphalt having a sufficient elastic recovery to allow products made therefrom to recover after traffic load had passed or weather related fatigue, and to products made therefrom, and to methods of making and using such compositions and products. In still yet another aspect, the present invention relates to asphalt compositions comprising an asphalt having a lower bond strength, to provide some flexibility to products made therefrom and allow then to move/give way under traffic loading and temperature sweeps (warm to cold e.g., summer/winter and cold front weather), and to products made therefrom, and to methods of making and using such compositions and products.
2. Description of the Related Art
U.S. Pat. No. 5,069,578, issued Dec. 31, 1991, to Bense et al., discloses a Bonded Friction Course (“BFC”) road asphalt system, known as the NOVACHIP process which utilizes a specialized “Spray Paver” machine to apply a thick layer of polymer modified tack coat immediately before a thin gap-graded Hot Melt Adhesive (“HMA”) asphalt layer is applied. This polymer modified tack coat wicks into the new gap graded mix by displacement and water vaporization. The tack coat provides a degree of adhesion or bonding between the layers and also acts to reduce slippage and sliding of the layers relative to other layers in the pavement structure during use or due to wear and weathering of the pavement structure. The thick application of the tack coat further seals minor cracks in the existing surface layer and forms a strong bond between the new HMA layer and the existing pavement.
Unfortunately, the NOVACHIP bonded friction course system can be prohibitively expensive due to the requirement that the specialized “Spray Paver” machine be used. In the 2011, each spray paver machine was reported to cost almost $500,000, and many paving contractors and state and county transportation agencies cannot justify the expense. However, without the use of the NOVACHIP Spray Paver, the thick layer of emulsified polymer modified tack coat used in a bonded friction course system would be very difficult to work with. The thick layer of emulsion tack coat would have a very slow cure rate, resulting in unacceptable delays and also tracking of the tack coat layer. Tracking occurs when the tack or bonding coat is picked up on the tires or tracks of vehicles traveling over the coated surface. Where this occurs, the asphalt compositions often are tracked onto other pavement surfaces causing disruption to the surrounding area. This tracking also reduces the effectiveness of the tack coat by displacing a portion of the intended volume from the area awaiting a new pavement layer.
Insufficient adhesion between a new layer of pavement and an existing base course, a previously laid pavement layer, or a prepared pavement surface can cause pavement separation and cracking during construction of the structure, as well as subsequent failures and premature deterioration of the pavement structure and/or surface. Such conditions often require costly repairs, can cause damage to vehicles traveling on the surface and may cause dangerous traffic conditions threatening damage to property and injury to vehicles and passengers.
To overcome the need for the specialized NOVACHIP “Spray Paver” machine, U.S. Patent Publication No. 20110206455, published Aug. 25, 2011, by Blacklidge, discloses a method of applying building a pavement structure using a polymer modified hot-applied tack coat that is applied with conventional asphalt distributors without the need for any specialized machinery. This polymer modified tack coat is non-adhesive at ambient temperatures, and, thus, also non tracking. The tack is applied while hot, but cools quickly. The subsequent application of hot mix asphalt results in a superior bond between the asphalt layer and the tack layer. It is particularly well suited to bonded friction course applications since it removes the necessity of specialized spray paving machinery and allows the use of conventional asphalt distributors and pavers.
Other asphalt related art includes the following patents and publications.
U.S. Pat. No. 4,198,177, issued Apr. 15, 1980, to Ray, Jr., et al., discloses methods and apparatus for repair of asphalt surfaces. The invention provides an improvement for those systems for repairing asphalt surfaces that include an emulsion tank, air pressure source, emulsion heating source, pneumatic tools and a vehicle having a fluid cooled engine and a utility body for containing asphalt repairing material. Specifically, the improvement disclosed is an emulsion tank removably mounted on said vehicle for containing a water soluable, air cured, sealer-bonding agent, an air compressor mounted on and driven by said vehicle engine, an air storage tank removably mounted on said vehicle and coupled to said compressor and pressurized thereby, means for selectively coupling air from said pressurized tank to said pneumatic tools and said emulsion tank and means coupling said vehicle cooling fluid to said emulsion tank for heating said emulsion to a usable temperature whereby certain of said pneumatic tools may be selectively driven by said compressed air in said storage tank to trim a damaged asphalt surface, spray emulsion over said trimmed are under pressure from said compressed air tank, and compact said asphalt repairing material into said trimmed and sealed area thereby repairing said damaged asphalt area.
U.S. Pat. No. 4,762,565, issued Aug. 9, 1988, to Graf, discloses an open-graded asphalt paving composition comprising about 80 to 97% by weight of an open-graded aggregate and about 3 to 20% asphalt, said composition being formed by successively mixing two asphalt-containing emulsions A and B with said aggregate wherein: emulsion A comprises about 40 to 75% by weight of a soft asphalt having a viscosity in the range of 50 to 1000 centistokes at 210° F. and 0.25 to 5% by weight of a emulsifier, and water as a continuous phase of said emulsion to make up 100% by weight; and emulsion B comprises about 40 to 75% by weight of a hard asphalt having a penetration 5 to 25 dmm at 77° F. and 0.25 to 5% by weight of a emulsifier, and water as a continuous phase of said emulsion to make up 100% by weight.
U.S. Pat. No. 4,836,857, issued Jun. 6, 1989, to Hopkins discloses asphalt additive compositions which comprise (A) a metallic organic strength improving compound and (B) an anti-strip compound. The metal of said metallic organic compound is selected from the group consisting of manganese, cobalt, copper, vanadium, molybdenum, cerium, iron, nickel, lead, zirconium, barium, calcium and zinc. The preferred metal is manganese. The anti-strip compound is designed to reduce water-induced damage to asphalt paving mixtures.
U.S. Pat. No. 5,735,634, issued Apr. 7, 1998 to Ulrich et al., discloses a road finisher, which is used for simultaneously applying at least two surface layers comprises a chassis, a travelling mechanism, at least two premix containers arranged on said chassis, a lateral distributor associated with the respective premix container and adapted to have material supplied thereto via a conveyor path extending in the chassis, and lateral outriggers attached to the chassis as well as a dragged road-surface applying device used for applying a surface layer and arranged on said outriggers, all road-surface applying devices being high-compaction road-surface applying screeds for recompaction-free application of a surface layer, and each high-compaction road-surface applying screed constituting a rear screed, when seen in the direction of movement, which is constructed as a high-compaction road-surface applying screed which is adapted to be used for applying and compacting concrete. In the method of applying surface layers by use of such a road finisher, the surface layers are applied one immediately after the other and in one operation in such a way that each first surface layer is highly compacted during application to such a degree that recompaction is no longer necessary and each following surface layer is applied to the highly-compacted surface layer and then, in turn, highly compacted to such a degree that recompaction is no longer necessary.
U.S. Pat. No. 5,769,567, issued Jun. 23, 1998 to Durand et al., discloses a process and a machine for forming a bonding layer for bonding a bituminous coated material layer on a support. The process includes application of a surface-active agent on the support, application of a bituminous emulsion on the surface-active agent on the support, and application of a breaking agent on the bituminous emulsion to form the bonding layer. A road-type coating made by the process and, therefore, including such a support layer, a bonding layer on the support, and a bituminous coated materials layer on the bonding layer. To perform the process, a machine includes a frame, a displacement mechanism on the frame, a bituminous-emulsion spreader on the frame, a surface-active agent applicator on the frame, and a breaking agent applicator on the frame.
U.S. Pat. No. 6,444,258, issued Sep. 3, 2002 to Terry, discloses a method and apparatus of treating a pavement surface, including the steps of: applying a layer of bituminous sealant at a predetermined temperature and application rate on the pavement surface; applying a layer of bituminous emulsion at a predetermined temperature and application rate on the first of bituminous sealant, wherein a thermal reaction occurs between the bituminous sealant and the bituminous emulsion so as to accelerate a material break and cure time for said layers; and, providing a layer of aggregate particles at a predetermined application rate on the layers of bituminous sealant and bituminous emulsion during the thermal reaction. The steps of the method are performed successively along a particular direction of advance at a rate which permits them to be accomplished within a predetermined time period. Additional steps of compacting the layers and/or applying an asphalt layer thereon may also be performed.
U.S. Patent Publication No. 20070141241, published Jun. 21, 2007 by Blacklidge, a method for bonding together an existing substrate layer and a pavement layer, such that a strong adhesive bond is formed by using a tack coat, provided by an asphalt emulsion, in between the layers as the bond coat. The tack coat layer is a low-tracking coating which cures quickly such that the pavement layer may be applied to the substrate, hours to days after the emulsion is applied to the substrate. The asphalt emulsion comprises at least a first phase of from about 30% to about 70% of an asphalt composition, about 30% to about 70% water, and about 0.1% to about 3.0% emulsifying agent, stabilizer and/or additives, or 0.1% to about 30% if polymeric or other additives are also included.
U.S. Pat. No. 7,503,724, issued Mar. 17, 2009 to Blacklidge, discloses a method for bonding together an existing substrate layer and a pavement layer, such that a strong adhesive bond is formed by using a tack coat, provided by an asphalt emulsion, in between the layers as the bond coat. The tack coat layer is a low-tracking coating which cures quickly such that the pavement layer may be applied to the substrate, hours to days after the emulsion is applied to the substrate. The asphalt emulsion comprises at least a first phase of from about 30% to about 70% of an asphalt composition, about 30% to about 70% water, and about 0.1% to about 3.0% emulsifying agent, stabilizer and/or additives, or 0.1% to about 30% if polymeric or other additives are also included.
U.S. Patent Publication No. 20090169901, published Jul. 2, 2009, by Blacklidge, discloses a method for bonding together an existing substrate layer and a pavement layer, such that a strong adhesive bond is formed by using a tack coat, provided by an asphalt emulsion, in between the layers as the bond coat. The tack coat layer is a low-tracking coating which cures quickly such that the pavement layer may be applied to the substrate, hours to days after the emulsion is applied to the substrate. The asphalt emulsion comprises at least a first phase of from about 30% to about 70% of an asphalt composition, about 30% to about 70% water, and about 0.1% to about 3.0% emulsifying agent, stabilizer and/or additives, or 0.1% to about 30% if polymeric or other additives are also included.
U.S. Patent Publication No. 20090182074, published Jul. 16, 2009 by Scholten, discloses an asphalt binder comprising 85 to 97.5 parts by weight of a bitumen and 16 to 2.5 parts by weigh of a polymer composition, wherein the polymer composition comprises: (i) from 2 to 8, preferably from 3 to 6 parts by weight of a styrenic block copolymer having at least two blocks of monovinylaromatic hydrocarbon (A) and at least one block of a conjugated diene (B), wherein the block copolymer composition has a vinyl content of at least 25% by weight, preferably from 25 to 40% by weight, based on the total diene content; (ii) from 0 to 5, preferably from 1 to 3 parts by weight of a styrenic diblock copolymer having one block of monovinylaromatic hydrocarbon (A) and one block of a conjugated diene (B); and (iii) from 0.5 to 3, preferably from 1 to 2.5 parts by weight of an ethylene-vinyl acetate copolymer, wherein the weight ratio of (i)+(ii):(iii) is from 2:1 to 6:1, preferably from 3:1 to 4:1. In addition, an asphalt mix is provided comprising 2 to 8 parts by weight of the asphalt binder of the present invention and 98 to 92 parts by weight of gap-graded aggregate or open-graded aggregate material. Furthermore, a porous pavement is claimed, produced from the open or gap-graded mixes, by compacting the asphalt mix mentioned above.
U.S. Patent Publication No. 20130154985, published Jun. 6, 2013, by Blacklidge et al., discloses a method of making an asphalt composition containing large quantities of ground tire rubber. Over 20% GTR by weight can be used in the asphalt composition without the GTR settling out. The method comprises a series of heating and blending and using a GTR stabilizer.
U.S. Pat. No. 8,840,717, issued Sep. 23, 2014, to Naidoo et al., discloses an additive package for warm-mix asphalt formulations for the pavement of road surfaces, said additive package comprising a) surfactant component, and b) an asphalt rheology modifying component, wherein said asphalt rheology modifying component comprises at least one of a i) a wax component and ii) a resin component. The invention also relates to a warm mix asphalt having improved compaction at lower temperatures, and to a pavement made from said warm mix asphalt.
Referring back to the asphalt compositions, products and methods of the '455 Publication, they utilize low Pen value (i.e. stiffer) asphalts, and these stiffer asphalts when utilized in trackless-type tacks, may perform poorly in thin pavements. Such hard Pen binders are becoming increasingly difficult to source and further, they are very variable in quality from refinery to refinery as well as crude oil source variations. Further, while asphalts of the '455 Publication are far more sprayable than the prior art NOVACHIP asphalts, there is still room for improvement in the sprayability of the '455 Publication asphalts that can be affected by having a lower rotational viscosity asphalt. Even further, the asphalts of the '455 Publication (as tested in the Example section below) have ductility of zero, meaning absolutely no capability of stretching or movement under traffic loading or weather related expansion and contraction. Still further, the asphalts of the '455 Publication (as tested in the Example section below) have an elastic recovery of zero, meaning will absolutely not allow the Tack Coat to recover after traffic load had passed or weather related fatigue. Finally, the asphalts of the '455 Publication has high bond strengths. Interestingly, the higher bond strength is not necessarily better since as the bond becomes too rigid and will not move/give way under traffic loading and temperature sweeps (warm to cold eg summer/winter and cold front weather). Therefore the asphalts of the '455 Publication also have room for improvement with a lower bond strength to provide/allow more movement.
Thus, in spite of the advances in the prior art, there is still a need in the art for improved asphalt compositions, improved asphalt products, and methods of making and using such compositions and products.
Thus, there is a need in the art for asphalt compositions comprising a high Pen (i.e., flexible) asphalt, and to products made therefrom, and to methods of making and using such compositions and products.
There is another need in the art for asphalt compositions comprising a lower rotational viscosity asphalt (especially in combination with maintaining a higher softening point), and to products made therefrom, and to methods of making and using such compositions and products.
There is even another need in the art for asphalt compositions comprising a more ductile asphalt to provide products made therefrom some capability of stretching or movement under traffic loading or weather related expansion and contraction, and to products made therefrom, and to methods of making and using such compositions and products.
There is still another need in the art for asphalt compositions comprising an asphalt having a sufficient elastic recovery to allow products made therefrom to recover after traffic load had passed or weather related fatigue, and to products made therefrom, and to methods of making and using such compositions and products.
There is yet another need in the art for asphalt compositions comprising an asphalt having a lower bond strength, to provide some flexibility to products made therefrom and allow then to move/give way under traffic loading and temperature sweeps (warm to cold e.g., summer/winter and cold front weather), and to products made therefrom, and to methods of making and using such compositions and products.
These and other needs in the art will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.